If you have a dual screen system each with their own pitot/static and AHRS units, each screen will have its own OAT sensor and calibration. If you have two screens and a single AHRS you should only adjust the screen that is wired to the OAT sensor.

1. Do both of your screens have Pitot/Static connections and AHRS?

2. Was it warming up in your hangar when you did this, or were you touching the OAT sensor?